Berries Production Guide

Insects and Mites

Avoid applying insecticides when bees are active. Refer to "Bee Poisoning" in the Pollination section of this guide.

Aphids

Hosts

Strawberry, many weeds especially chickweed, and wild rose.

Damage

Aphids spread plant viruses, even from a short feeding period.

Shallot aphid. Flower stalks become short and thick. This is followed by misshapen blossoms and failure to fruit. Generally the entire plant is stunted with twisted yellowish leaves. Damage is caused by small populations and occurs in spotty areas.

Strawberry aphid. Rarely causes direct damage but spreads viruses.

Identification

The shallot aphid is very small and is found only on the youngest leaves. The strawberry aphid is found mainly on the under surface of youngest, emerging leaves.

Nymph. Resemble wingless adults but smaller.

Adult. Small and pale green. Winged and wingless forms are present.

Life History

Shallot aphid. Overwinters as nymphs and adults in strawberry crowns or weeds. Aphids move from weeds to strawberries in the very early spring when the weeds are removed. Winged aphids leave the plantings in June and reappear starting mid-August.

Strawberry aphid. Overwinters as nymphs or adults in strawberry crowns or as black eggs on older leaves. Under coastal conditions, the eggs hatch in February. Aphids are most abundant in the spring when the plants are growing quickly. Many generations occur each season.

Monitoring

Inspect field weekly starting in early April. Be sure to check the underside of new, folded leaves emerging from the crown.

Management

Several strawberry viruses are spread by aphids. They must be controlled to lengthen the useful life of a planting. The best way to reduce virus spread within a field or from farm to farm is for everyone in an area to control aphids in their strawberries.

Cultural control

Control weeds, especially chickweed.

Biological control

A number of beneficials help to control aphids. Lady beetles, lacewings, syrphid flies and parasitic wasps can reduce aphids to non-damaging levels. However, where viruses are a concern, it is usually necessary to apply an insecticide.

Chemical control

Apply:

Beleaf 50SG (50% flonicamid) at 0.12 to 0.16 kg/ha (48 to 64 g/acre) as a foliar spray in enough water to obtain good coverage. Use the higher rate when insect pressure is heavy or when foliage is dense. Repeat as necessary. Allow a minimum of 7 days between applications. Do not apply more than 3 times per season. Beleaf may be applied up to the day of harvest; or

Admire 240F or Alias 240SC (240g/L imidacloprid) at 0.85 to 1.3 L/ha (340 to 520 mL/acre) as an over the row drench in 2000 L/ha (800 L/acre) of water. Apply in early spring when growth begins and aphids are first detected. Apply to established plantings only. The highest rate will provide the longest-term residual control. Do not apply during bloom. Do not apply more than once per season. Do not apply within 30 days of harvest; or

Assail 70WP (70% acetamiprid) at 56 to 86 g/ha (22 to 34 g/acre) in a minimum of 187 L/ha (75 L/acre) of water by ground application. Use the higher rates under heavy insect pressure. Use enough water to obtain good coverage. Do not apply more than twice per season. Do not apply more than once every 7 days. Do not apply during bloom as Assail is toxic to bees directly exposed to treatment. Do not apply within 1 day of harvest; or

Sivanto Prime (200g/L flupyradifurone) at 500-750 ml/ha (196-295 ml/acre) in a minimum of 100 L/ha (40 L/acre) of water as a foliar spray. Do not apply more than once every 10 days. Do not exceed 2000 ml/ha (787 ml/acre) per season. Can be applied up to the day of harvest.

Exirel (100 g/L cyantraniliprole) at 500 to 1500 mL/ha (200 to 600 mL/acre) in enough water to obtain good coverage. Do not apply during bloom as Exirel is toxic to bees. Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre). Do not apply 1 days of harvest, or

Note: It is recommended that a small area be tested to demonstrate safety to fruit and leaves before using in large areas.

Cygon 480 or Lagon 480E (480 g/L dimethoate) at 2.25 L/ha (0.9 L/acre). Apply when aphids are first detected and repeat as needed. Do not apply more than 3 times per year. Do not apply within 7 days of harvest; or

Note: Do not use Lagon or Cygon on crops to be exported to the U.S.

Caterpillars

Hosts

Strawberry, thistle, vetch, clover and a wide range of other plants.

Damage

Young larvae feed on young, unopened leaves and tie or web these together. They also damage green berries immediately after the blossom period. Older larvae enter ripening berries beneath the calyx caps. One larva may injure many berries.

Identification

The larva is light cream to greyish, with a tan head and a stripe down each side of the body. Mature larvae are about 19 mm long. The moths are whitish, slender and weak fliers. They are seldom seen. Larvae of other species can be brown, black, or green.

Life History

The moths lay eggs in rough fence posts, power poles and rough-barked trees. In early spring, young larvae are blown by the wind to many host plants. There is only one generation per year. The larvae move from leaf buds to blossoms and then fruit. The moths begin to fly towards the end of strawberry harvest.

Other leafroller species have two generations per year.

Monitoring

Watch for early signs of attack by looking at the unfolding leaves in late April to early May.

Management

Caterpillars are periodic pests, often not needing control. Larval feeding in early spring can affect yield and should be controlled if more than 10% of plants checked have caterpillars.

Chemical control

Spray when young leaves are tied together by webbing, at the first sign of blooms, will usually prevent fruit injury. Use one of the following:

Malathion 85E (85% malathion) at 975 mL/ha (390 L/acre) of water and spray thoroughly. Repeat if necessary. Do not apply within 3 days of harvest; or

Malathion 25W (25% malathion) at 2.75 to 4.25 kg/ha (1.1 to 1.7 kg/acre). Spray for thorough coverage. Do not apply within 3 days of harvest; or

Note: Do not apply Malathion sprays unless the temperatures are above 20°C;

Sevin XLR Plus (466 g/L carbaryl) at 2.5 to 5.8 L/ha (1.0 to 2.3 L/acre). Use in 1000 to 2000 L/ha (400 to 800 L/acre) spray volume. Repeat at intervals of 7 to 10 days or as necessary. Do not apply within 2 days of harvest; or

Success 480SC (480 g/L spinosad) at 145 to 182 mL/ha (58 to 73 mL/acre) in 300 to 500 L/ha of water. Use the upper rate under high insect pressure and/or on large larvae. Apply a maximum of 3 times per year and do not apply within 3 days of harvest; or

Entrust 80W (80% spinosad) at 80 to 109 g/ha (32 to 44 g/acre) or Entrust SC (240 g/L spinosad) at 267 to 364 mL/ha (107 to 146 mL/acre)in 300 to 500 L/ha of water. Use the upper rate under high insect pressure and/or on large larvae. Apply a maximum of 3 times per year and do not apply within 3 days of harvest. Entrust is OMRI approved for organic production.

Leatherjackets (Coastal Area)

Hosts

Strawberry, grasses.

Damage

Larvae feed on the roots, crowns and leaves of plants. In new plantings, transplants can be cut at soil level as occurs with cutworms. Damage is most severe in March, April and May. Populations are highest in damp or heavy soils. Normally only a problem in new fields which were in grass the previous September.

Identification

Larvae. Leatherjackets are the larvae of crane flies. The larvae have a tough, grey skin. They are about 3 cm long when mature.Pupae. Elongate and brown with rows of spines along the top and bottom surfaces. The back end is pointed. Empty pupal cases can be seen at the surface of the soil after crane fly emergence.

Life History

The European marsh cranefly, the main species, lays eggs during September. Larvae (about 3 mm long) hatch from these eggs within two weeks. The leatherjackets are present until the next year in June, growing to 2.5 to 3 cm long.

Monitoring

If a weedy piece of land or grassland is to be used for planting, test for leatherjackets in the spring before cultivation. Apply a 0.1% Diazinon 500 EC solution as a drench to the soil. If leather jackets are present they will come to the surface. Watch for damage in planted fields shortly after planting.

Management

Cultural control

Control weeds especially in fall, winter and early spring.

Chemical control

None.

Lygus Bugs (Tarnished Plant Bug)

Hosts

Strawberry, raspberry, weeds, clover and vegetable crops.

Damage

Adults and nymphs feed by sucking sap from all parts of the plant. Lygus bugs feeding on the flowers or developing green berries are the main cause of misshapen berries or “monkeyfaces”. This occurs because the nymphs or adults destroy the developing embryos in the seeds, preventing the growth of the fruit tissue beneath the seed.

There are other causes for misshapen fruit (see “Misshapen Fruit” below). Be sure to correctly identify the cause of the misshapen fruit before deciding to spray. The seeds on fruit damaged by lygus are hollow inside but are the same size in both the undamaged and monkeyfaced areas. The damage is probably not lygus if the seeds are smaller in the monkeyfaced area.

Identification

Nymphs. Look like large, green aphids. But unlike aphids, they are very fast moving.

Adults. Shield-shaped, flattened bugs about 6 mm in length. They are a mottled brownish colour with a characteristic white V-shaped pattern on their back. They quickly run or fly when disturbed.

Life History

Adult bugs overwinter under plant debris. They lay eggs in the spring in the plant stems. Nymphs appear at blossom time. Bugs from one or two generations will feed on blossoms and fruit until September.

Monitoring

Start monitoring for the appearance of nymphs once blossoming starts.

To monitor fields, walk slowly through the field and randomly select plants to inspect for lygus. At each plant, look for adults on the leaves. To find the nymphs, shake the flower clusters over a tray or white paper. Nymphs are usually found feeding and hiding in the flower clusters where they cannot be seen by visual inspection. Sample about 13 evenly-distributed plants per acre. Make weekly field inspections throughout the blossoming and fruit development period.

Be especially alert monitoring strawberry fields located beside hay fields. Lygus bugs often move into the strawberry field when the hay is cut and begins to wilt. The lygus bugs are forced to find new feeding areas. They can suddenly appear in the strawberries causing extensive crop injury.

Research has shown that properly installed yellow sticky traps can be used to detect adult lygus activity.

Control sprays should be applied if one 1 lygus nymph is found per 20 plants.

Management

Cultural control

Good weed control within and beside strawberry plantings helps keep lygus bugs at low levels. Be sure to destroy weeds when lygus are still in the nymph stage and cannot fly. When weeds are destroyed after this, lygus adults will move into the strawberries. If the weeds are not destroyed, lygus adults will move into the crop when the weeds dry up.

Biological control

Natural predators of lygus are bigeyed bugs, damsel bugs, and lacewings. Lygus bugs are parasitized by a number of braconid wasps and several tachinid flies. However, none of these insects will prevent lygus from causing economic damage when lygus numbers are high.

Chemical control

For the best results, time sprays to kill the earliest stages of nymphs. Apply controls as soon as nymphs become active in the strawberries. Try to limit the number of treatments and carefully select sprays. All the listed pesticides should kill lygus. Ripcord will also kill natural predators of two-spotted mites and could lead to a build-up of this problem. Do not apply these pesticides when bees are in the field.

When chemical control is needed, use:

Group 3

Matador 120EC, Silencer 120EC (120 g/L lambda-cyhalothrin)or Warrior (122 g/L lambda cyhalothrin) at 104 mL/ha (42 mL/acre). Apply 7 to 10 days after first bloom and repeat 7 to 10 days later if required. Do not use more than 3 applications per year. Do not apply within 7 days of harvest; or

Mako or Ripcord 400EC (407 g/L cypermethrin) at 250 mL/ha (100 mL/acre). Use 300 to 500 L (120 to 200 L/acre) of water per hectare. Apply at early bloom (about 10%) and repeat in 10 to 12 days at the end of full bloom. Do not apply within 7 days of harvest; or

Decis 5.0EC or Decis (50g/L deltamethrin) at 200 mL/ha (80 mL/acre). Apply when insects are present or insect feeding signs are evident and repeat if needed. Very toxic to fish. Do not apply near ditches and water courses. Do not use more than 2 applications per year. Do not apply within 14 days of harvest; or

Note: Decis is not acceptable for some markets. Check with your packer before using

Group 2A

Thionex EC (400 g/L endosulfan) at 2.5 L/ha in up to 2000 L of water (1 L/acre in up to 800 L water). Apply at first bloom and repeat 10 days later. Do not apply more than 2 times per season. Do not apply within 7 days of harvest; or

Restricted re-entry: Do not re-enter fields within 4 days for scouting, hand-weeding, mulching or irrigation, 7 days for other activities.

Thionex 50W (50% endosulfan) at 2.0 kg/ha in up to 2000 L of water (0.8 kg/acre in up to 800 L water). Apply at first bloom and repeat 10 days later. Do not apply more than 2 times per season. Do not apply within 12 days of harvest; or

Restricted re-entry: Do not re-enter fields within 7 days for scouting, hand-weeding, mulching or irrigation, 12 days for other activities.

Group 15

Rimon 10EC (10% novaluron) at 835 mL/ha (334 mL/acre) in enough water to ensure good coverage. Apply when lygus bugs are first detected. Additional applications at 10-14 day intervals may be required. Do not apply more than 3 times per season. Do not apply within 1 day of harvest; or

Note: Rimon is not acceptable for some markets. Check with your packer before using.

Group 4

Assail 70WP (70% acetamiprid) at 84 to 210 g/ha (34 to 84 g/acre)in a minimum of 187 L/ha (75 L/acre) of water by ground application. Use the higher rates under heavy insect pressure. Use enough water to obtain good coverage. Do not apply more than twice per season. Do not apply more than once every 7 days. Do not apply during bloom as Assail is highly toxic to bees directly exposed to treatment. Do not apply within 1 day of harvest; or

Group 4A

Clutch 50WDG or Clothianidin (50% clothianidin) at 448 g/ha (180 g/acre) in at least 500 L/ha (200 L/acre) of water. Apply prior to the start of bloom when lygus bugs are detected. Do not apply more than once per season. Do not apply within 1 day of harvest. Clutch is highly toxic to bees exposed to direct treatment or residues on blooming crops. Do not apply during bloom or when bees are present; or

Note: Clutch 50 WDG, Clothianidin and Assail 70 WP are highly toxic to bees and their use is prohibited when strawberries are in bloom.

Group 1B

Cygon 480AG or Lagon 480E (480 g/L dimethoate) at 2.75 L/ha (1.1 L/acre). Apply at first bloom and repeat 10 to 12 days later if needed. Do not apply within 7 days of harvest.

Note: Do not use Lagon or Cygon on crops to be exported to the U.S.

Group 9C

Beleaf 50SG (50% flonicamid) at 0.20 kg/ha (80 g/acre) as a foliar spray in enough water to obtain good coverage. Apply when lygus bugs are first detected. Will provide suppression only. Repeat as necessary. Allow a minimum of 7 days between applications. Do not apply more than 3 times per season. Beleaf may be applied up to the day of harvest.

Spittlebugs

Hosts

Strawberry, clovers, grasses, many weeds and ornamental plants.

Damage

Leaves and stems become twisted and thickened, and fruit stems shortened, from nymphs sucking and removing plant sap. Yield can be reduced with large populations. Also, pickers object to the frothy spittle.

Identification

Nymphs. Young nymphs are white to lemon-yellow and look like fat aphids. They feed inside the frothy spittle.Adults. Wedge shaped, greyish-brown insects about 6 mm long which jump and fly readily.

Life History

There is one generation per year. Adults lay orange eggs on the plants during and after the harvest. These eggs overwinter on the plant or in debris. They hatch in early spring and the first spittle masses, containing the nymphs, occur usually in late April to May. Adults appear about late May and are present until late fall.

Monitoring

Watch for spittle masses from just before bloom through the harvest. During harvest the nymphs change to adults.

Management

Chemical control

If spittlebugs were a problem the previous year or when they are seen apply one of the following sprays. Sprays applied for lygus bugs or aphids usually also control spittlebugs. Do not apply if bees are in the field.

Matador 120EC or Silencer 120EC (120 g/L lambda-cyhalothrin) at 104 mL/ha (42 mL/acre). Apply when spittlebugs are first noticed. Do not use more than 3 applications per year. Allow a 7 day interval between treatments. Do not apply within 7 days of harvest; or

Mako or Ripcord 400EC (407 g/L cypermethrin) at 175 mL/ha (70 mL/acre). Use 300 to 500 L/ha (120 to 200 L/acre) of water. Do not apply within 7 days of harvest; or

Thionex EC (400 g/L endosulfan) at 2.5 L/ha in up to 2000 L of water (1 L/acre in up to 800 L water). Apply at first bloom and repeat 10 days later. Do not apply more than 2 times per season. Do not apply within 7 days of harvest; or

Restricted re-entry: Do not re-enter fields within 4 days for scouting, hand-weeding, mulching or irrigation, 7 days for other activities.

Thionex 50W (50% endosulfan) at 2.0 kg/ha in up to 2000 L of water (0.8 kg/acre in up to 800 L water). Apply at first bloom and repeat 10 days later. Do not apply more than 2 times per season. Do not apply within 12 days of harvest; or

Restricted re-entry: Do not re-enter fields within 7 days for scouting, hand-weeding, mulching or irrigation, 12 days for other activities.

Dibrom (864 g/L naled) at 1.1 L/ha (450 mL/acre). Use 100 to 300 L of water/ha (40 to 120 L/acre). Do not apply when the temperature is over 32°C. Do not re-enter treated fields within 48 hours of application. Do not apply within 4 days of harvest; or

Sevin XLR Plus (466 g/L carbaryl) at 2.5 to 5.8 L/ha (1 to 2.3 L/acre). Use in 1000 to 2000 L/ha of water. Do not apply within 2 days of harvest; or

Sevin 50W (50% carbaryl) at 2.25 to 4.5 kg/500 L. Use 1100 to 2,250 L/ha (440 to 900 L/acre) of water. Do not apply within 1 day of harvest.

Spotted Wing Drosophila

Hosts

Berries, stone fruits and numerous wild hosts

Damage

Female flies lay eggs under the skin of ripe fruit shortly before harvest. Larvae hatch and begin to feed within the fruit, causing softening in the area of feeding. There can be several larvae in a fruit, which hastens softening and fruit collapse.

Identification

Adults: 2-3 mm (1/8 inch) long, brownish with red eyes and clear fly-like wings. . Males have a black/grey spot on the end of each wing, as well as two black ‘combs’ or bands on each front leg. The females do not have spots or leg bands. Females have saw-like egg-laying organs (ovipositors) that are used to cut into fruit skin. Ovipositors are easier to see when extended. A hand-lens or dissecting microscope is needed to identify ovipositor.

Life History

SWD overwinter as adult flies. In spring flies become active and lay eggs in ripening fruit. Based on climate model predictions, there could be up to 5 generations per year in BC. Generations overlap as flies are relatively long-lived particularly at temperatures of 20°C and cooler. Based on Japanese literature, a female can lay eggs for 10-59 days, with 7-16 eggs laid per day, and average 384 eggs per female. Eggs hatch in 2-72 hours, larvae mature in 3-13 days, and pupae reside in fruit or outside of fruit for 3-15 days. In the lab at constant temperature, one generation takes 50 days at 12°C, 21-25 days at 15°C, 19 days at 18°C, 8.5 days at 25°C, and 7 days at 28°C. Adults are attracted to and feed on ripe and decaying fruit.

Monitoring

Flies can be monitored with cup-like traps baited with apple cider vinegar. Place traps when the temperature is consistently over 10°C and/or before fruit starts to ripen. Hang traps in the plant canopy in a shady location. Check traps once per week and look for the SWD adults in the bait solution. Use a hand lens or other magnifier to see the female ovipositor. Replace the bait solution each week. Suspect fruit can also be collected and inspected for larvae.

Management

Cultural control

Where practical, remove or bury cull fruit to eliminate additional feeding and breeding sites. Keep equipment and processing areas free of old fruit. Think beyond the borders of your farm and be aware of host plants in adjacent fields. Encourage neighbours to also manage for SWD. Shorten picking interval where possible: pick early, clean and often.

Biological control

To date, there are no commercially available biological controls for SWD. Research is underway to identify potential predators and/or parasites that may be useful in managing SWD.

Chemical control

Chemical control will be required if trapping shows that adult SWD flies are present in the field when berries begin to ripen. Adults are the target and are killed by direct spray contact and/or when they are exposed to residues of insecticide on the treated fruit and leaves.

Consider the following when planning a spray program:

1. All of the recommended products are toxic to bees. Avoid application when crops are blooming and bees are in the field. If sprays are necessary during this time, they should be applied at night.
2. Use enough water and pressure to ensure adequate coverage (up to 500 L/ha of water). Flies prefer to feed in the lower, shaded part of the canopy.
3. Use spray equipment that will allow effective coverage. Currently, no products are registered for aerial application.
4. To limit development of resistance, rotate between the recommended products.
5. A 7 – 14 day spray interval may be necessary to protect fruit through the ripening period depending on temperature and pest pressure.
6. A post-harvest spray may be necessary to prevent flies from building up on residual fruit and spreading to adjacent later ripening crops.

The following products are registered for control of SWD:

Delegate WG (25% spinetoram) at 280 g/ha (112 g/acre). Do not apply more than 3 times per year. Allow a re-treatment interval of at least 7 days. Do not apply within 1 day of harvest.

Entrust SC (240 g/L spinosad) at 333 to 444 mL/ha (133 to 178 mL/acre). Minimum re-treatment interval is 3 days. It is OMRI approved for organic production. Do not apply more than 3 times per year and do not apply with 1 day of harvest.

The following products received emergency registration for SWD in 2017:

Mako (407 g/L cypermethrin) at 150 mL/ha (60 mL/acre). Apply only once per crop per year. Apply between June 1 and November 30, 2017. Do not apply within 2 days of harvest; or

Malathion 85E (85% malathion) at 1 L/ha (400 mL/acre) in up to 1000 L of water. Apply when the temperature is 20°C or more. Apply between June 1 and November 30, 2017. Do not apply more than 2 times per year. Do not apply within 3 days of harvest; or

Strawberry (Cyclamen) Mite

Host

Strawberry.

Damage

Young, folded leaflets in the centre of the plant are attacked first. Affected leaves are “crinkled” or “puckered” when unfolded. Older leaves are darker green, twisted or distorted and feel brittle. If the leaf stems and runners are attacked, they are shortened and become rough or bumpy. Severely infested plants are stunted and yields reduced.

Identification

This mite is very hard to see without magnification. Large numbers are found on the midrib of very young leaflets. The eggs look like a small pile of salt.

Life History

The mites overwinter as adults deep in the crown of the plant. They lay eggs in spring and throughout the summer. Serious damage is not seen until harvest or after harvest. New plantings can be infested by contaminated runner plants.

Monitoring

Start to watch for deformed leaves, and shortened and rough leaf stems in early spring when growth starts. Damage is most noticeable during the spring and early summer. Strawberry mites attack all varieties of strawberries.

Management

Biological control

Usually these mites are kept in control by predatory mites. If the predatory mites are killed by insecticides, the strawberry mites can become a problem.

Chemical control

If Thiodan is applied for lygus or spittlebug control, separate sprays may not be necessary. However, when sprays are necessary, apply as soon as possible after growth starts in the spring. Use a high pressure and high volume spray to reach the well-hidden mites (2400 kPa and 4500 L/ha (1800 L/acre) of water).

If the mite damage is noticed before or during harvest, apply a spray after renovation when plants start regrowth. Another spray two weeks later may be needed to obtain good control.

Spray with:

Agri-mek 1.9%EC (19 g/L abamectin) at 1.0 L/ha (0.4 L/acre) in at least 375 L/ha (150 L/acre) of water. Do not apply more than twice per growing season. Apply when strawberry (cyclamen) mites first appear and reapply if monitoring indicates mites are still present. Allow 7-10 days between applications. Do not apply more than 2 L/ha (787 L/acre) per season. Do not apply within 3 days of harvest; or

Agri-mek SC (84 g/L abamectin) at 225 ml/ha (88 ml/acre) with 0.1-0.5% v/v non ionic surfactant in at least 375 L/ha (150 L/acre) of water. Apply when strawberry (cyclamen) mites first appear and reapply if monitoring indicates mites are still present. Allow 7-10 days between applications. Do not apply within 3 days of harvest; or

Thionex EC (400 g/L endosulfan) at 5 L/ha in 4000 to 8000 L of water (2.0 L/acre in 1600 to 3200 L water). Apply before flower bud formation in the spring. Do not apply within 7 days of harvest; or

Restricted re-entry: Do not re-enter fields within 4 days for scouting, hand-weeding, mulching or irrigation, 7 days for other activities.

Thionex 50W (50% endosulfan) at 2.0 to 4.0 kg/ha in 4000 to 8000 L of water (0.8 to 1.6 kg/acre in 1600 to 3200 L water). Apply before flower bud formation in the spring. Do not apply within 12 days of harvest; or

Restricted re-entry: Do not re-enter fields within 7 days for scouting, hand-weeding, mulching or irrigation, 12 days for other activities.

Two-spotted Spider Mite

Host

Strawberry, raspberry, tree fruits, and a wide variety of shrubs and vegetables.

Damage

These mites feed on the lower side of strawberry leaves causing a whitish flecking on the upper surface. Large populations cause the leaves to dry up and turn brown. Yields are reduced, especially if populations are large early in the season. Local research shows a 10 to 15% yield reduction when populations reach 30 to 60 mites per leaflet during harvest.

Identification

Two-spotted spider mites are very tiny. From April to October they are pale yellow to green, with two large black spots on the back and sides of the body. Orange overwintering females appear in October. Fine silk webbing is typically present on the underside of the leaves.

Life History

Orange adult female mites overwinter from October to February on the host plant and in the leaf litter. Mites can often be found on the underside of a mature leaf, near the petiole. In February the over-wintering mites become active and change appearance to yellow-green with two black spots. After feeding a few days, they start laying eggs on the old and newly emerging leaves. Eggs hatch in 1 to 2 weeks and the young mites become reproductive adults in another 1 to 3 weeks. Mite numbers increase rapidly in the spring and summer by a succession of generations. Mites develop and reproduce faster at higher temperatures, so more generations occur and numbers may increase rapidly in hot dry weather – particularly if the native predators have been eliminated by pesticides.

Monitoring

Monitor mite levels throughout the growing season to minimize crop losses and maximize spray effectiveness. Start monitoring in late March when the first new leaves are fully opened (mature). Use this fast and easy method to monitor mites in strawberries:

Walk in at least 2 diagonals through the field, picking and examining 200 leaflets for two-spotted mites. Examine only 1 of these leaflets for each sample and space the samples so that the entire field is covered. Use a magnifying glass (10x minimum) to examine the leaflets. Count the number of leaflets with mites and proceed as in Table 6.

Management

Biological control

As an alternative to spraying, release predator mites (Amblyseius fallacis) in newly planted fields at the rate of 7,000 per acre about ten days after the first aphid spray. This should establish the predator mites in the field. These mites feed on the two-spotted mites but require time to reduce pest numbers.

If sprays are applied for other pests, try to use chemicals that do not affect the predator mites. Some predators usually survive dimethoate and diazinon sprays. Assume no predators will survive after Matador, Decis and Ripcord sprays. Re-apply Amblyseius at the rate of at least 7,000 per acre. Predator mites and additional information may be obtained from a pest management consultant.

Table 6. Thresholds for two-spotted spider mite control

Number of leaflets out of 200 leaflets with at least one mite

Action recommended

0 to 20

sample again in 3 weeks

21 to 40

sample again in 2 weeks

41 to 90

sample again in 1 week

91 to 120

a spray is advisable if the number of leaflets with mites increased by more than 25 leaflets in 1 week; otherwise sample again in 1 week.

above 120

a spray is advisable if the number of leaflets with mites increased during the previous week, otherwise sample again in 1 week.

Chemical control

Begin applications when mite numbers are above the thresholds in Table 6 above. To slow the development of resistance, rotate sprays from the following list of miticides:

Apollo SC (500 g/L clofentezine) at 500 mL/ha in 500-1000 L of water/ha (200 mL/acre in 200-400 L of water/acre). Apply at first sign of mite activity. Apollo acts only against eggs and very young larval stages (motiles). The older immatures and adults are not killed. Most predatory mites will survive. Do not apply more than one application per season. Do not apply within 15 days of harvest; or

Note: Apollo is not acceptable for some markets. Check with your packer before using.

Oberon (240 g/L spiromesifen) at 0.88 to 1.16 L/ha (350 to 460 mL/acre) with adequate pressure and in enough water to obtain good coverage on both sides of the leaves. Apply when mite populations begin to build. Oberon is most effective against the egg and nymph stages of mites. Do not apply more than 3 times per season. Do not re-enter fields within 3 days of application. Do not apply within 3 days of harvest;or

Nexter (75% pyridaben) at 300 to 600 g/ha (120 to 240 g/acre) in at least 1000 L/ha (400 L/acre) of water when mites first appear. Do not apply more than twice per season. Do not apply within 10 days of harvest; or

Agri-mek 1.9%EC (19 g/L abamectin) at 1.0 L/ha (0.4 L/acre) in at least 375 L/ha (150 L/acre) of water. Do not apply more than twice per growing season. Do not apply within 3 days of harvest; or

Agri-mek SC (84 g/L abamectin) at 225 ml/ha (88 ml/acre) with 0.1-0.5% v/v non ionic surfactant in at least 375 L/ha (150 L/acre) of water. Allow 7-10 days between applications. Do not apply within 3 days of harvest; or

Nealta (200 g/L cyflumetofen) at 1.0 L/ha (400 mL/acre) in at least 500 L/ha (200 L/acre) of water. Do not apply more than 2 times per season. Allow a minimum of 14 days between applications. Do not apply within 1 day of harvest.

Thrips

Western flower thrips (Frankliniella occidentalis)

European flower thrips (Frankliniella intonsa)

Hosts

Strawberry, and numerous ornamentals, food crops and weeds.

Damage

Damage is primarily limited to strawberry fruit and appears as russeting, bronzing, splitting or development of a leathery texture particularly around the calyx end of the fruit. Adults and larvae feed by removing sap from punctures they make in the plant tissue. Thrips do not cause monkeyfaced fruit.

Identification

Thrips are small, slender insects, 0.5 - 1 mm in length. Adults have two pairs of narrow wings fringed with long, fine hairs. Their colour varies from yellow to brown or blackish-brown. Young thrips are shiny yellow and lack wings. Insects are seen most readily in flowers, under bracts and petals and under the calyx of fruit.

Life Cycle

Adults move from field margins and grass fields when these spring feeding sites are mowed or dry out. Thrips lay eggs into the plant leaf tissue along the main vein. The eggs hatch in 5 to 7 days. Young thrips hatch and feed on plant parts. They pass through nymph and pupal stages before becoming adults. Flower thrips pupate in the soil. Timing of the complete life cycle is temperature dependent. The adults can live and feed for up to 45 days. Thrips can be present throughout the growing season, but are more abundant in warm summer weather.

Monitoring

There has been no action threshold developed for thrips in strawberries in BC; however, information from California suggests that controls should be applied when10 thrips per flower are detected. Using a hand lens, inspect flowers and fruit by gently prying apart flower parts and looking under the calyx. Alternatively, shake flowers onto a flat surface and count the number of thrips that fall out. Use yellow or blue sticky traps to monitor for adults; Western flower thrips are more attracted to blue than yellow. Be especially vigilant when nearby hay fields are harvested.

Management

Dayneutral (everbearing) strawberries are at greater risk of thrips damage than June-bearing crops.

Cultural control

Naturally occurring beneficial insects help manage thrips, including pirate bugs (Orius spp.) and predatory mites (Amblyseius spp.). Other biological control agents are used in greenhouses for thrips management, including foliar application of beneficial nematodes and other predatory mites; however, these products have not been tested on strawberries.

Chemical control

If numerous thrips are found in flowers and on developing fruit, insecticides should be applied. Good coverage is critical as thrips are hidden within flowers and developing fruit. Rotate products to prevent development of resistance. Apply:

Delegate WG (25% spinetoram) at 200 to 280 g/ha (80 to 112 g/acre) when high levels of thrips are detected. A repeat application within 3 or 4 days may be necessary if pest pressure is heavy. Do not apply more than 3 times per season. Do not apply within 1 day of harvest;or

Note: Delegate is toxic to bees and should not be applied when bees are actively foraging. It may be toxic to aphid parasites if they are directly contacted.

Exirel (100g/L cyantraniliprole) at 1000 to 1500 mL/ha (400 to 600 mL/acre) in enough water to obtain good coverage. Do not apply during bloom as Exirel is toxic to bees. Do not apply more than 4 times per season or a maximum of 4.5 L/ha (1.8 L/acre). Do not apply 1 days of harvest.

Note: It is recommended that a small area be tested to demonstrate safety to fruit and leaves before using in large areas.

Malathion, Ripcord, Matador when applied for other pests will aid in controlling thrips.

Weevils

Host

Strawberry, raspberry and some ornamentals.

Damage

Most of the damage is done by the larvae (grubs) which eat the roots. Some can tunnel into the crown causing plants to wilt and die in localized areas of the field. The adults feed on strawberry foliage resulting in characteristic notching. Foliage can become seriously damaged when a large number of weevils are present.

Identification

Several species are present in BC including black vine weevil, strawberry root weevil, woods weevil, clay coloured weevil and obscure root weevil. The most problematic species in BC is the black vine weevil.

Larvae. Creamy-white, legless grubs which, except for woods weevil, are C-shaped. The head is often brown and they do not have legs.

Life History

Larvae overwinter in the soil. Some adults also survive the winter in protected areas or old buildings. These adults become active within plantings or begin to invade new areas by mid-April. The invasion can continue throughout the summer until about mid-October. Eggs are often laid in a fold made by the adult on the edge of a leaf, or in the soil, from early-May onward. All the adults are female and can lay eggs. On hatching, the young larvae move into the soil to feed on fine rootlets and overwinter. There is only one generation each year.

Monitoring

Look for fresh leaf notches especially before blossoming and during harvest. Plants close to old berry plantings, pastures or wooded areas are usually the first attacked. The adults feed on the foliage at night. Sweep plants with an insect net at night to determine if adults are present or use a flashlight to inspect leaves and crowns. Be sure to correctly identify the weevil species so control sprays can be accurately timed, if required. The main emergence of black vine weevils occurs in June

Management

Chemical control

Control is directed against the adult beetles which must be killed before they lay eggs. Sprays should be applied only to areas where fresh leaf notches are seen.

Use one of the following:

Matador 120EC, Silencer 120EC (120 g/L lambda-cyhalothrin)or Warrior (122 g/L lambda cyhalothrin) at 104 ml/ha (42 mL/acre). Apply when feeding damage is first detected. Do not use more than 3 applications per year. Do not apply within 7 days of harvest; or

Actara 25WG (25% thiamethoxam) at 210 to 280 g/ha (84 to 112 g/acre) in sufficient water to obtain coverage of foliage. Apply when adult weevils or weevil damage is detected. Repeat application if insect populations rebuild. Use the higher rate for heavy infestations. Do not apply more than twice per season. Do not apply within 3 days of harvest; or

Note: Actara is highly toxic to bees exposed to direct treatment or to residues on blooming crops and weeds. Do not apply Actara or allow it to drift onto blooming crops or weeds if bees are foraging in/or adjacent to the treatment area. After an Actara application, wait at least 5 days before placing the beehives near the treated field.

Admire applied to control aphids should also reduce adult weevils numbers.

Malathion 85E (85% malathion) at 1.35 L/ha (540 L/acre) of water or Malathion 500 E (500 g/L malathion) at 2.75 L/ha (1.1 L/acre) of water or Malathion 50EC (50% malathion) at 2.5 to 3.75 L/ha (1 to 1.5 L/acre). Spray for thorough coverage. Repeat if necessary. Do not apply within 3 days of harvest.

Wireworms

Damage

Wireworms bore into strawberry crowns and destroy them. In heavy infestations, they feed on established plants and greatly reduce the yield, and weaken or kill the plants. Wireworms may enter fruit that is in contact with the ground and become a serious contaminant.

Identification

Yellowish-brown, shiny, slender, hard-bodied worms 5 to 25 mm long.

Management

Plan for control in field preparation for new plantings. For information on controlling wireworms, refer to “General Berry Pests” in this guide.